[Midnightbsd-cvs] mports: Makefile: Update the png shared lib version

[vganji at midnightbsd.org]

Log Message:
-----------
Update the png shared lib version

Modified Files:
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    mports/graphics/xli:
        Makefile (r1.6 -> r1.7)
        (http://cvsweb.midnightbsd.org/mports/graphics/xli/Makefile?r1=1.6&r2=1.7)